Thread rolling fixture



Nov. 12, 1963 L- W. B EDKER THREAD ROLLING FIXTURE Filed March 6, 1963 IN V EN TOR.

MM Mm fin ma 0 United States Patent fiFice 3,119,202 TIHQEAD RQLLING FIXTURE Leo William Bedlser, 21615 Beaconsfield, East Detroit, Mich. Filed Mar. 6, H63, Ser. No. 264,477 7 Claims. ((31. 80-6) The present invention relates to thread rolling, and more particularly, to a thread rolling fixture adjustable to roll threads on work pieces of different diameter.

The present application is a continuation-in-part of my prior copending application Serial No. 627,173, filed December 10, 1956, and now abandoned.

The invention relates generally to the type of thread rolling in which a pair of thread rolls are provided in rigidly spaced relation with their axes extending substantially parallel to each other. A rotating work piece is moved into the space between the thread rolls. The thread rolls are geared together with lost motion means in the gearing providing for differential rotation between the thread rolls. In practice, the holder is positioned such that a particular one of the thread rolls engages the rotating work piece in advance of the other thread roll. Engagement between the work piece and the first thread roll initiates rotation of the first thread roll, taking up lost motion in the gearing and effecting timed rotation of the second thread roll. Thus, when the second thread roll contacts the periphery of the work piece, it is rotating in properly timed relation and at substantially synchronous surface speed. Thereafter, the thread rolling fixture and work piece are relatively moved to cause the work piece to enter fully into the space between the thread rolls, thus forming the threads to full depth thereon.

In accordance with the present invention, one of the thread rolls is mounted on a shaft which is radially adjustable toward and away from the axis of the other thread roll. Adjusting screws are provided so that this thread roll may be firmly clamped in radially adjusted position. The other thread roll is provided with means for effecting radial adjustment thereof by exactly predetermined increments while maintaining exact alignment or orientation of the axis of the other thread roll. This is of extreme importance because it is essential for the thread rolls to be adjusted with great accuracy as to the orientation or alignment of their axes in space. Thus, the thread roll which is radially adjustable by exactly predetermined increments without disturbing the orientation of its axis may be used after adjustment as location means for setting the other of the two rolls.

With the foregoing in mind, it is an object of the present invention to provide a thread rolling fixture comprising means for mounting a pair of thread rolls in laterally spaced relation, and means for effecting predetermined incremental radial adjustment of one thread roll with respect to the other without disturbing the orientation of its axis with respect to the fixture.

It is a further object of the present invention to provide a thread roll comprising a fixture, a pair of thread rolls carried by the fixture in laterally spaced relation, means for effecting predetermined incremental adjustment of one of the thread rolls radially of the other, and means for effecting adjustment of the other tiread roll relative to the said one thread roll.

It is a feature of the present invention to provide in a thread rolling fixture, a pair of eccentric bushings for mounting a rotatable thread roll, and means for effecting exactly predetermined angular adjustment of both of said bushings to effect lateral adjustment of the associated thread roll without disturbing its orientation in space.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing,

wherein:

FIGURE 1 is a side elevational view of the thread rolling fixture, with parts broken away.

FIGURE 2 is a sectional-view on the line Z2 of FIGURE 1.

FIGURE 3 is a plan view of the thread rolling fixture.

FIGURE 4 is a fragmentary view of the part shown'in FIGURE 2, with the eccentric bushing reversed.

The rolling fixture comprises a body It being bifurcated to provide forwardly extending laterally spaced arms 12 and 14. The body .16 has a rearwardly extending shank 16 provided with an opening 18 by means of which the fixture may be mounted for swinging movement about the axis of the opening 18.

The body it is mounted for relative movement to a work piece W. Conveniently, the thread rolling fixture may be mounted on a slide movable horizontally as seen in FIGURE 1, toward and away from the work piece W which is to be threaded. In use the axis of the pivot mounting provided by the opening 18 is parallel to the axis of the work piece W.

The fixture comprises a first shaft 2%} adapted to support a thread roll 22 and a second shaft 24 adapted to support a thread roll 26. The thread rolls 22 and 26 are disposed with their axes substantially parallel to the axis of the Work piece W or slightly inclined thereto as suggested in my prior United States Patent 2,690,089. Conveniently, the attachment may be employed on an automatic screw machine in which case the Work piece W is driven in rotation and rotation is imparted to the thread rolls through engagement with the work piece W.

Preferably, as disclosed in my prior United States Patent 2,701,484, resilient means are provided urging one of the thread rolls 22 or 26 into engagement with the work piece W ahead of the other thread roll. Thus, upon initial engagement rotation is imparted to the first thread roll.

Interconnecting the thread rolls (which have been omitted for clarity in FIGURE 2) are gears including lost motion mechanism. The gear 30 is disposed at the v side of the thread roll 22 rotatably mounted on the shaft 2%. The gear 32 is located at the side of the thread roll 26 mounted on the shaft 24. Either or both of the gears 30 and 32 are provided with a lost motion connection with the adjacent thread roll. Intermediate the gears 30 and 32 are the gears 34, 36, and 38. The arrangement is such that when one of the rolls, as for example the roll 22, contacts the work piece W upon traverse of the fixture to the left in FIGURE 1, and is driven by frictional contact therewith, the lost motion connection between the thread rolls and gears is taken up and thereafter the thread roll 26 is driven through the train of gears at a speed such that itssurface speed is substantially identical to the surface speed of the work piece W. When the thread roll 26 engages the work piece W it is accordingly in accurately located angular relation, due to the gearing and is turning at substantially synchronous speed relative to the Work piece W. Further traverse of the fixture to the left, as seen in FIGURE 1, is accompanied by rotation of the thread rolls as driven by the work piece, and the differential rotation necessary to continued traverse of the fixture is provided by the lost motion connection between the thread rolls and gears.

As soon as the fixture has moved to a position such that the center of the work piece is on-center between the centers of the thread rolls, or slightly beyond, the fixture is rapidly withdrawn and the operation is complete.

One of the critical factors in successful thread rolling is maintaining the position or orientation of the thread rolls relative to the work piece with exactness. How- Patented Nov. 12, 1963 I ever, it is essential that some adjustability be provided not only to accommodate different diameter work pieces, but also to bring the thread rolls into exactly proper relationship for a succession of identical work pieces. The necessary relative radial adjustment between the thread rolls may not be provided by simply making each of the two rolls separately adjustable, because in this way orientation of the axes of the thread rolls in space,

or with respect to the axis of the pivot mounting provided by the opening 18, would be lost and it would become a dilficult problem to reset the rolls.

In accordance with the present invention one of the rolls, as for example the roll 22 carried by the shaft 2% is provided with means for effecting predetermined incremental radial adjustment relative to the other thread roll without disturbing orientation of its axis. This is accomplished by providing a pair of eccentric bushings or shaft mounting members 48 and 42. The bushings are formed with cylindrical exterior surfaces 44 and 48 and are provided with radially extending end flanges 50 and '52 respectively. The arm 12 is provided with aligned openings 54 and 56 in which the bushings 49 and 42 are rotatable. These openings are of circular cross-section, and their centers provide centers of adjustment about which said bushings are angularly adjustable. Extending diametrically through the openings 54 and 56 are elongated screw receiving passages 58 and 60. The bushings 40 and 42 are provided with tapped openings 62 and 64 for the reception of the positioning screws 66 and 63 respectively.

7 The shaft 20 adjacent opposite ends is provided with flattened locating seats 7 and 72 respectively adapted to be en aged by the inner ends of the screws 66 and 68. From an inspection of FIGURE 2 it will be observed that when the inner ends of the screws 66 and 68 are seated against the flattened shaft seats 70 and '72 respectively, the outer slotted ends of the screws extend into portions of the passages 58 and 60. Accordingly, with the parts in the position illustrated in. FIGURE 2, it will of course beapparent that the screws 66 and 681101: only position the shaft 20 in the arm 12of the fixture, but also retain the bushings 40 and 42 in one of two predetermined angular positions of adjustment in the fixture and particularly, prevent rotation of the bushings about their axes.

It will further be observed that the bushings 40 and 42 have shaft receiving openings 74 and 76 which are substantially eccentric with respect to the outside diameter of the cylindrical portions'44 and 48 of the bushings.

If it is desired to effect a wider separation between the rolls 22 and 26 the fOllOWing procedure is followed: The screws 66 and 68 are withdrawn sufiiciently to disengage the shaft 20 which may thereafter be withdrawn. Thereafter, the screws 66 and 68 are advanced until the heads thereof are located within the bushings 40 and 42, at which time the bushings may be rotated 180 degrees, thus aligning the screws 66 and 68 with the lower ends of the passages 58 and 66'. At this time the screws 66 and 68 may be engaged through the lower ends of the passages to cause the heads of the screws to extend therein. Thejshaft may be re-inserted and the screwstightened, at which time they again perform the dual function of retaining the shaft in position and also retaining the bushings in the new position of adjustment. This position of adjustment is illustrated in FIGURE 4. It will be apparent that rotation of both bushings 40 and 42 through 180 degrees will not eifect any change in orientation in space of the shaft 20 but will result in movement of the shaft toward the shaft 24 by an amount determined exactly by the eccentricity of the inner and outer cylindrical surfacesofthe bushings. This of course is because the two bushings 40 and 42 will both have been given the same angular adjustment. Accordingly, shaft 20 will retain its parallelism with the pivot mounting provided by opening 18.

Alternatively, the adjustment may be effected by withdrawing the screws 66 and 68 completely through the bushings, rotating the bushings degrees, and re-inserting the screws through the opposite ends of the passages 58 and 60.

The shaft 24 which supports the thread roll 26 is provided with means for effecting gradual radial adjustment thereof. This means comprises threaded openings in the body 19 receiving the screws 8t 82, 84 and 86. It will be apparent that vertically upward movement of the shaft 2 3- may be accomplished for example by retracting the screws 8%} and 84 and advancing the screws 82 and 36. This operation may be carried out to effect exactly the desired spacing between the shafts 26 and 24. At the same time, the final orientation 'of the shaft 24 may be brought about by comparison with the shaft 2% as for example by suitable calipers, gauges or the like.

Thus, the incremental adjustment of the shaft 29 is carried out in such a way as to maintain the orientation of the shaft without disturbance, and fine adjustment as to relative spacing is thereafter accomplished by adjusting the shaft 24, while preserving its orientation by comparison with that of the shaft 24}.

Obviously, the eccentric bushing may be provided with two or more threaded openings spaced at accurately predetermined angles with respect to each other so that the bushing may have more than 'two predetermined positions of angular adjustment.

The drawing and the foregoing specification constitute a description of the improved thread rolling fixture in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A thread rolling fixture comprisinga holder having spaced support arms, each of said arms being bifurcated to receive a thread roll between the bifurcations thereof, the bifurcations of one of said arms having aligned cylindrical bushing-receiving openings therein, eccentric bushings in said openings, a first roll support shaft having end portions received in said bushings, lock means for locking each of said bushings in one of a relatively few predetermined positions of angular adjustment, said lock means including means effective to prevent locking of said bushings except when in one .of said predetermined angular positions, the other of said arms having elongated aligned slots in its bifurcations extending toward the said one arm, a second roll supporting shaft having end portions received in said slots, and separate means for efiecting continuous, as contrasted with incremental, adjustment of the end portions of said second shaft in said slots toward and away from sm'd first shaft.

2. A thread rolling fixutre comprising a holder having a spaced support arms, each of said arms being bifurcated to receive a thread roll between the bifurcations thereof, the bifurcations of one of said arms having aligned cylindrical bushing-receiving openings therein, eccentric bushings in said openings, a first roll support shaft having end portions received in said bushings, a plurality of locating openings in each of said bifurcations extending radially of the bushing-receiving opening therein, corresponding ones of said locating openings in the tWo bifurcations of said one arm being in alignment axially of said aligned bushing-receiving openings, threaded radial holes in 581d bushings, and set screws in said holes dimensioned to extend into said bushings to engage a shaft portion therein and to extend radially outwardly from said bushings when g g ng a shaft portion therein so that said bushings and screws can support a shaft only when turned to one.

of a number of predetermined positions of angular adjustment in which the radially outwardly projecting portions of said set screws are received in said radially, extending locating openings.

3. A thre'ad rolling fixture comprising a holder having p q d support arms, each of said arms being bifurcated to receive a thread roll between the furcations thereof, the furcations of one of said arms having aligned bushing-receiving openings therein, eccentric bushings in said openings, a first roll support shaft having end portions received in said bushings, means for mounting each of said bushings in a corresponding one of a relatively few predetermined positions of angular adjustment in one of said openings including means effective to prevent mounting of said bushings except when in one of said predetermined angular positions, the other of said arms having elongated aligned slots in its furcations extending toward the said one arm, a second roll supporting shaft having end portions received in said slots, and separate means for effecting continuous, as contrasted with incremental, adjustment of the end portions of said second shaft in said siots toward and away from said first shaft.

4. A thread rolling fixture comprising a holder having mounting means establishing a pivot axis about which said holder is movable, spaced support arms on said holder, said arms having portions spaced apart circumferentially with respect to said pivot axis, each of said arms being bifurcated to receive a thread roll between the furcations thereof, adjustable shaft mounting members carried by the furcations of one of said arms, means for locating said members in corresponding ones of a limited number of predetermined positions of angular adjustment about centers fixed relative to said furcations, and for preventing mounting of said members except when in one of said predetermined positions, said centers occupying a line parallel to the pivot axis of said mounting means, said members having thereon means for supporting the end portions of a shaft with the same eccentricity with respect to said fixed centers, the other of said arms having elongated parallel slots in its furcations extending toward said one arm, and separate means for effecting continuous, as contrasted with incremental, adjustment of a second shaft in said slots toward and away from said first shaft.

5. A thread rolling fixture comprising a holder having mounting means establishing a pivot axis about which said holder is movable, spaced support arms on said holder, said arms having portions spaced apart circumferentially with respect to said pivot axis, each of said arms being bifurcated to receive a thread roll between the furcations thereof, adjustable shaft mounting members carried by the furcations of one of said arms, a first shaft having its end portions carried by said members, means for locating said members in corresponding ones of a limited number of predetermined positions of angular adjustment about centers fixed relative to said furcations, and for preventing mounting of said members except when in one of said predetermined positions, said centers occupying a line parallel to the pivot axis of said mounting means, said members having thereon means for supporting the end portions of said shaft with the same eccentricity with respect to said fixed centers, the other of said arms having elongated parallel slots in its furcations extending toward said one arm, a second shaft having its end portions received in said slots, and separate means for effecting continuous, as contrasted with incremental,

adjustment of said second shaft in said slots toward and away from said first shaft.

6. A thread rolling fixture comprising a holder having mounting means establishing a pivot axis about which said holder is movable, spaced support arms on said holder, said arms having portions spaced apart circumferentially with respect to said pivot axis, each of said arms being bifurcated to receive a thread roll between the furcations thereof, adjustable shaft mounting members carried by the furcations of one of said arms, means for 10- cating said members in one of two corresponding positions of angular adjustment degrees apart about centers fied relative to said furcations, and for preventing mounting of said members except when in one of said predetermined positions, said centers occupying a line parallel to the pivot axis of said mounting means, said members having thereon means for supporting the end portions of a shaft with the same eccentricity with respect to said fixed centers, the other of said arms having elongated parallel slots in its furcations extending toward said one arm, and separate means for effecting continuous, as contrasted with incremental, adjustment of a second shaft in said slots toward and away from said first shaft.

7. A thread rolling fixtm'e comprising a holder having mounting means establishing a pivot axis about which said holder is movable, spaced support arms on said holder, said arms having portions spaced apart circumferentially with respect to said pivot axis, each of said arms being bifurcated to receive a thread roll between the furcations thereof, adjustable shaft mounting members carried by the furcations of one of said arms, a first shaft having its end portions carried by said members, means for locating said members in one of two corresponding positions of angular adjustment 180 degrees apart about centers fixed relative to said furcations, and for preventing mounting of said members except when in one of said predetermined positions, said centers ocoupying a line parallel to the pivot axis of said mounting means, said members having thereon means for support-ing the end portions of said shaft with the same eccentricity with respect to said fixed centers, the other of said arms having elongated parallel slots in its furcations extending toward said one arm, a second shaft having its end portions received in said slots, and separate means for effecting continuous, as contrasted with incremental, adjustment of said second shaft in said slots toward and away from said first shaft.

References Cited in the file of this patent UNITED STATES PATENTS 233,029 Burkhardt Dec. 30, 1879 1,107,621 Landis Aug. 18, 1914 1,773,737 Lindquist Aug. 26, 1930 2,690,089 Bedker Sept. 28, 1954 2,694,322 Nell Nov. 16, 1954 2,701,484 Bedker Feb. 8, 1955 FOREIGN PATENTS 753,484 Great Britain Aug. 1, 1956 

4. A THREAD ROLLING FIXTURE COMPRISING A HOLDER HAVING MOUNTING MEANS ESTABLISHING A PIVOT AXIS ABOUT WHICH SAID HOLDER IS MOVABLE, SPACED SUPPORT ARMS ON SAID HOLDER, SAID ARMS HAVING PORTIONS SPACED APART CIRCUMFERENTIALLY WITH RESPECT TO SAID PIVOT AXIS, EACH OF SAID ARMS BEING BIFURCATED TO RECEIVE A THREAD ROLL BETWEEN THE FURCATIONS THEREOF, ADJUSTABLE SHAFT MOUNTING MEMBERS CARRIED BY THE FURCATIONS OF ONE OF SAID ARMS, MEANS FOR LOCATING SAID MEMBERS IN CORRESPONDING ONES OF A LIMITED NUMBER OF PREDETERMINED POSITIONS OF ANGULAR ADJUSTMENT ABOUT CENTERS FIXED RELATIVE TO SAID FURCATIONS, AND FOR PREVENTING MOUNTING OF SAID MEMBERS EXCEPT WHEN IN ONE OF SAID PREDETERMINED POSITIONS, SAID CENTERS OCCUPYING A LINE PARALLEL TO THE PIVOT AXIS OF SAID MOUNTING MEANS, SAID MEMBERS HAVING THEREON MEANS FOR SUPPORTING THE END PORTIONS OF A SHAFT WITH THE SAME ECCENTRICITY WITH RESPECT TO SAID FIXED CENTERS, THE OTHER OF SAID ARMS HAVING ELONGATED PARALLEL SLOTS IN ITS FURCATIONS EXTENDING TOWARD SAID ONE ARM, AND SEPARATE MEANS FOR EFFECTING CONTINUOUS, AS CONTRASTED WITH INCREMENTAL, ADJUSTMENT OF A SECOND SHAFT IN SAID SLOTS TOWARD AND AWAY FROM SAID FIRST SHAFT. 